Create a ProfileDependencyManager to order ProfileKeyedService destruction.

chrome/browser/profiles/profile_dependency_manager.cc

+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/browser/profiles/profile_dependency_manager.h"
+
+#include <algorithm>
+#include <deque>
+
+#include "chrome/browser/profiles/profile_keyed_service.h"
+#include "chrome/browser/profiles/profile_keyed_service_factory.h"
+#include "content/common/notification_service.h"
+
+class Profile;
+
+void ProfileDependencyManager::AddComponent(
+    ProfileKeyedServiceFactory* component) {
+  all_components_.push_back(component);
+  destruction_order_.clear();
+}
+
+void ProfileDependencyManager::RemoveComponent(
+    ProfileKeyedServiceFactory* component) {
+  all_components_.erase(std::remove(all_components_.begin(),
+                                    all_components_.end(),
+                                    component),
+                        all_components_.end());
+
+  // Remove all dependency edges that contain this component.
+  EdgeMap::iterator it = edges_.begin();
+  while (it != edges_.end()) {
+    EdgeMap::iterator temp = it;
+    ++it;
+
+    if (temp->first == component || temp->second == component)
+      edges_.erase(temp);
+  }
+
+  destruction_order_.clear();
+}
+
+void ProfileDependencyManager::AddEdge(ProfileKeyedServiceFactory* depended,
+                                       ProfileKeyedServiceFactory* dependee) {
+  edges_.insert(std::make_pair(depended, dependee));
+  destruction_order_.clear();
+}
+
+// static
+ProfileDependencyManager* ProfileDependencyManager::GetInstance() {
+  static ProfileDependencyManager* manager =
+      Singleton<ProfileDependencyManager>::get();
+  return manager;
+}
+
+ProfileDependencyManager::ProfileDependencyManager() {
+  // Listen for all Profile destruction messages so that we can rebroadcast
+  // them to all Factories in a safe order.
+  registrar_.Add(this,
+                 NotificationType::PROFILE_DESTROYED,
+                 NotificationService::AllSources());
+}
+
+ProfileDependencyManager::~ProfileDependencyManager() {}
+
+void ProfileDependencyManager::BuildDestructionOrder() {
+  // Step 1: Build a set of nodes with no incoming edges.
+  std::deque<ProfileKeyedServiceFactory*> queue;
+  std::copy(all_components_.begin(),
+            all_components_.end(),
+            std::back_inserter(queue));
+
+  std::deque<ProfileKeyedServiceFactory*>::iterator queue_end = queue.end();
+  for (EdgeMap::const_iterator it = edges_.begin();
+       it != edges_.end(); ++it) {
+    queue_end = std::remove(queue.begin(), queue_end, it->second);
+  }
+  queue.erase(queue_end, queue.end());
+
+  // Step 2: Do the Kahn topological sort.
+  std::vector<ProfileKeyedServiceFactory*> output;
+  EdgeMap edges(edges_);
+  while (!queue.empty()) {
+    ProfileKeyedServiceFactory* node = queue.front();
+    queue.pop_front();
+    output.push_back(node);
+
+    std::pair<EdgeMap::iterator, EdgeMap::iterator> range =
+        edges.equal_range(node);
+    EdgeMap::iterator it = range.first;
+    while (it != range.second) {
+      ProfileKeyedServiceFactory* dest = it->second;
+      EdgeMap::iterator temp = it;
+      it++;
+      edges.erase(temp);
+
+      bool has_incoming_edges = false;
+      for (EdgeMap::iterator jt = edges.begin(); jt != edges.end(); ++jt) {
+        if (jt->second == dest) {
+          has_incoming_edges = true;
+          break;
+        }
+      }
+
+      if (!has_incoming_edges)
+        queue.push_back(dest);
+    }
+  }
+
+  if (edges.size()) {
+    NOTREACHED() << "Dependency graph has a cycle. We are doomed.";
+  }
+
+  std::reverse(output.begin(), output.end());
+  destruction_order_ = output;
+}
+
+void ProfileDependencyManager::Observe(NotificationType type,
+                                       const NotificationSource& source,
+                                       const NotificationDetails& details) {

[Miranda Callahan, 2011/03/29 19:07:04]

Should probably make sure that the NotificationType is PROFILE_DESTROYED here.

[Elliot Glaysher, 2011/03/29 22:18:29]

No longer applicable.

+  Profile* profile = Source<Profile>(source).ptr();
+
+  if (destruction_order_.empty())
+    BuildDestructionOrder();
+
+  for (std::vector<ProfileKeyedServiceFactory*>::const_iterator it =
+           destruction_order_.begin(); it != destruction_order_.end(); ++it) {

[Miranda Callahan, 2011/03/29 19:07:04]

nit: indent

[Elliot Glaysher, 2011/03/29 22:18:29]

Indentation is correct? Breaking a statement is previous indentation plus 4,
right?

+    (*it)->ProfileShutdown(profile);
+  }
+
+  for (std::vector<ProfileKeyedServiceFactory*>::const_iterator it =
+           destruction_order_.begin(); it != destruction_order_.end(); ++it) {

[Miranda Callahan, 2011/03/29 19:07:04]

nit: indent

+    (*it)->ProfileDestroyed(profile);
+  }
+}